This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This study was performed as a combination antibody pharmacokinetic (PK) and efficacy study to evaluate an immunotherapy based on the inhibition of IL-10 activity using a humanized monoclonal antibody. The desired effect was to increase the immune responsiveness in three chimpanzees chronically infected with HCV and observe the reduction or elimination of viremia.